I have painted my dogs nails before. I don't see how that is harming/abusing your pet. Same with dying your pet, as long as it's done properly I see no problem with it. Dyes for Animals are vegetable based and harmless for your pet. I think as long as you are using those things correctly and humanely it is the owners choice whether they want a pink dog or not. LOL
As for plastic surgery and cropping ears, I don't agree with it. Now, it's not like I won't be friends with someone because their dog has cropped ears but I would never do that to MY dog. (Although my dog is a poodle so he would look quite goofy.
Each to his own though..